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Message-ID: <CAFp+6iHhUvLhAKGPARS8RUfmO8RGcTrumvYb7QjJXbFD1nUuig@mail.gmail.com>
Date: Mon, 14 Apr 2014 19:19:20 +0530
From: Vivek Gautam <gautamvivek1987@...il.com>
To: Tomasz Figa <tomasz.figa@...il.com>
Cc: Kishon Vijay Abraham I <kishon@...com>,
Tomasz Figa <t.figa@...sung.com>,
Linux USB Mailing List <linux-usb@...r.kernel.org>,
"linux-samsung-soc@...r.kernel.org"
<linux-samsung-soc@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
linux-doc@...r.kernel.org, Greg KH <gregkh@...uxfoundation.org>,
Felipe Balbi <balbi@...com>,
Kukjin Kim <kgene.kim@...sung.com>,
Kamil Debski <k.debski@...sung.com>,
Jingoo Han <jg1.han@...sung.com>,
Sylwester Nawrocki <sylvester.nawrocki@...il.com>
Subject: Re: [PATCH V4 1/5] phy: Add new Exynos5 USB 3.0 PHY driver
Hi,
On Mon, Apr 14, 2014 at 7:14 PM, Tomasz Figa <tomasz.figa@...il.com> wrote:
> On 14.04.2014 15:05, Kishon Vijay Abraham I wrote:
>>
>>
>>
>> On Monday 14 April 2014 05:35 PM, Vivek Gautam wrote:
>>>
>>> Hi Kishon,
>>>
>>>
>>> On Mon, Apr 14, 2014 at 5:24 PM, Kishon Vijay Abraham I <kishon@...com>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On Wednesday 09 April 2014 04:36 PM, Tomasz Figa wrote:
>>>>>
>>>>> Hi Vivek,
>>>>>
>>>>> Please see my comments inline.
>>>>>
>>>>> On 08.04.2014 16:36, Vivek Gautam wrote:
>>>>>>
>>>>>> Add a new driver for the USB 3.0 PHY on Exynos5 series of SoCs.
>>>>>> The new driver uses the generic PHY framework and will interact
>>>>>> with DWC3 controller present on Exynos5 series of SoCs.
>>>>>> Thereby, removing old phy-samsung-usb3 driver and related code
>>>>>> used untill now which was based on usb/phy framework.
>>>>>>
>>>>>> Signed-off-by: Vivek Gautam <gautam.vivek@...sung.com>
>>>>>> ---
>>>>>> .../devicetree/bindings/phy/samsung-phy.txt | 42 ++
>>>>>> drivers/phy/Kconfig | 11 +
>>>>>> drivers/phy/Makefile | 1 +
>>>>>> drivers/phy/phy-exynos5-usbdrd.c | 668
>>>>>> ++++++++++++++++++++
>>>>>> 4 files changed, 722 insertions(+)
>>>>>> create mode 100644 drivers/phy/phy-exynos5-usbdrd.c
>>>>>
>>>>>
>>>>> [snip]
>>>>>
>>>>>> + Additional clock required for Exynos5420:
>>>>>> + - usb30_sclk_100m: Additional special clock used for PHY
>>>>>> operation
>>>>>> + depicted as 'sclk_usbphy30' in CMU of Exynos5420.
>>>>>
>>>>>
>>>>> Are you sure this isn't simply a gate for the ref clock, as it can be
>>>>> found on
>>>>> another SoC that is not upstream yet? I don't have documentation for
>>>>> Exynos
>>>>> 5420 so I can't tell, but I'd like to ask you to recheck this.
>>>>>
>>>>>> +- samsung,syscon-phandle: phandle for syscon interface, which is used
>>>>>> to
>>>>>> + control pmu registers for power isolation.
>>>>>> +- samsung,pmu-offset: phy power control register offset to
>>>>>> pmu-system-controller
>>>>>> + base.
>>>>>> +- #phy-cells : from the generic PHY bindings, must be 1;
>>>>>> +
>>>>>> +For "samsung,exynos5250-usbdrd-phy" and
>>>>>> "samsung,exynos5420-usbdrd-phy"
>>>>>> +compatible PHYs, the second cell in the PHY specifier identifies the
>>>>>> +PHY id, which is interpreted as follows:
>>>>>> + 0 - UTMI+ type phy,
>>>>>> + 1 - PIPE3 type phy,
>>>>>> +
>>>>>> +Example:
>>>>>> + usb3_phy: usbphy@...00000 {
>>>>>> + compatible = "samsung,exynos5250-usbdrd-phy";
>>>>>> + reg = <0x12100000 0x100>;
>>>>>> + clocks = <&clock 286>, <&clock 1>;
>>>>>> + clock-names = "phy", "usb3phy_refclk";
>>>>>
>>>>>
>>>>> Binding description above doesn't mention "usb3phy_refclk" entry.
>>>>>
>>>>>> + samsung,syscon-phandle = <&pmu_syscon>;
>>>>>> + samsung,pmu-offset = <0x704>;
>>>>>> + #phy-cells = <1>;
>>>>>> + };
>>>>>
>>>>>
>>>>> [snip]
>>>>>
>>>>>> diff --git a/drivers/phy/phy-exynos5-usbdrd.c
>>>>>> b/drivers/phy/phy-exynos5-usbdrd.c
>>>>>> new file mode 100644
>>>>>> index 0000000..ff54a7c
>>>>>> --- /dev/null
>>>>>> +++ b/drivers/phy/phy-exynos5-usbdrd.c
>>>>>
>>>>>
>>>>> [snip]
>>>>>
>>>>>> +static int exynos5_usbdrd_phy_probe(struct platform_device *pdev)
>>>>>> +{
>>>>>> + struct device *dev = &pdev->dev;
>>>>>> + struct device_node *node = dev->of_node;
>>>>>> + struct exynos5_usbdrd_phy *phy_drd;
>>>>>> + struct phy_provider *phy_provider;
>>>>>> + struct resource *res;
>>>>>> + const struct of_device_id *match;
>>>>>> + const struct exynos5_usbdrd_phy_drvdata *drv_data;
>>>>>> + struct regmap *reg_pmu;
>>>>>> + u32 pmu_offset;
>>>>>> + int i;
>>>>>> +
>>>>>> + /*
>>>>>> + * Exynos systems are completely DT enabled,
>>>>>> + * so lets not have any platform data support for this driver.
>>>>>> + */
>>>>>> + if (!node) {
>>>>>> + dev_err(dev, "no device node found\n");
>>>>>
>>>>>
>>>>> This error message is not very meaningful. I'd rather use something
>>>>> like "This
>>>>> driver can be only instantiated using Device Tree".
>>>>
>>>>
>>>> how about just adding depend_on OF in Kconfig?
>>>
>>>
>>> Already added a depend on 'OF'. Copying below the part of Kconfig in this
>>> patch.
>>
>>
>> Alright.. Do we need the check then? If config_OF is enabled devices will
>> be
>> created using device tree no?
>
>
> Not necessarily. Enabling support for OF doesn't mean that it is the only
> boot method that can be used. Legacy board files may be still available. I'm
> not sure why someone would try to instantiate this driver from them, though.
True, we don't have a scope of instantiating this driver using old
platform device and
old legacy board files.
So we don't need this check then, right ?
--
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India
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